Author 
































































































































































































































































UNIVERSITY OF ILLINOIS BULLETIN 

Issued Weekly 

Vol. XIV AUGUST 20, 1917 No. 51 

[Entered as aeoond-claaa matter Deo. 11, 1912, at the Post Office at Urbana, Ill., under the Act of Aug. 24, 1912.) 


THE UTILIZATION OP PYRITE 
OCCURRING IN ILLINOIS 
BITUMINOUS COAL 

BY 

E. A. HOLBROOK 



CIRCULAR No. 5 


ENGINEERING EXPERIMENT STATION 

Published by the University of Illinois, Urbana 


Price: Twenty Cents 

European Agent 
Chapman & Hall, Ltd., London 







T HE Engineering Experiment Station was established by act of the 
Board of Trustees, December 8, 1903. It is the purpose of the 
Station to carry on investigations along various lines of engineer¬ 
ing and to study problems of importance to professional engineers and 
to the manufacturing, railway, mining, constructional, and industrial 
interests of the State. 

The control of the Engineering Experiment Station is vested in the 
heads of the several departments of the College of Engineering. These 
constitute the Station Staff and, with the Director, determine the char¬ 
acter of the investigations to be undertaken. The work is carried on 
under the supervision of the Staff, sometimes by research fellows as 
graduate work, sometimes by members of the instructional staff of the 
College of Engineering, but more frequently by investigators belonging 
to the Station corps. 

The results of these investigations are published in the form of 
bulletins, which record mostly the experiments of the Station’s own staff 
of investigators. There will also be issued from time to time, in the 
form of circulars, compilations giving the results of the experiments of 
engineers, industrial works, technical institutions, and governmental 
testing departments. 

The volume and number at the top of the title page of the cover 
are merely arbitrary numbers and refer to the general publications of 
the University of Illinois; either above the title or below the seal is given 
the number of the Engineering Experiment Station bulletin or circular 
which should be used in referring to these publications. 

For copies of bulletins, circulars, or other information address the 

Engineering Experiment Station, 
Urbana, Illinois 


UNIVERSITY OF ILLINOIS 
ENGINEERING EXPERIMENT STATION 


Circular No. 5 


August, 1917 


THE UTILIZATION OF PYRITE OCCURRING 
IN ILLINOIS BITUMINOUS COAL 


BY 

E. A. HOLBROOK 

ii 



\ ♦ » 


ENGINEERING EXPERIMENT STATION 

Published by the University of Illinois, Urbana 













CONTENTS 



PAGE 

Introduction.5 

I. Occurrence and Nature of Pyrite in Coal .... 7 

1. Composition of Pyrite.7 

2. Pyrite in Illinois Coals.8 

3. Origin of Pyrite.11 

4. Recovery of Pyrite.12 

5. Market Conditions.13 

6. Pyrite in Refuse Heaps.15 

7. Oxidation of Pyrite.15 

8. Description of Machinery used in Preparing Pyrite 

and Outline of Washing Tests.17 

II. Summary of Tests.18 

9. Machinery Required.18 

10. Percentage of Recovery.18 

11. Estimated Operating Result.20 

12. Method of Operation.20 

13. The Tests and the Results.24 

14. The Size of Screen Holes.27 

15. Losses.32 

16. Water Supply.32 

17. Design of Plant.35 

18. Cost of Plant.38 

19. Summary of Capital Costs.40 

Appendix.41 

20. Analysis of Pyrite Ores for Sulphur Content . . 41 

21. Additional Directions and Precautions .* . . .42 


4 > 

* * * 


D. of D. 
SEP ? 1917 























) 


LIST OF TABLES 

NO. PAGE 

1. Amount of Sulphur and Pyrite in Refuse of Coal at Various Illinois Coal 

Preparation Plants.16 

2. Estimated Operating Statement of a Pyrite Plant of a Capacity of 

50 Tons per 8-hour Day.20 

3. Flow Sheet Reduced to a Basis of Sulphur Content, Showing the Amount 

of Sulphur in Each Product Based on the Output of a Plant Having 
a Capacity of 50 Tons per 8-hour Day.23 


LIST OF FIGURES 


NO. • PAGE 

1. Pyrite Lense in Illinois Coal.9 


2. Close View of Pyrite Lense in Coal, One-third Actual Size .... 10 

3. Close View of Pyrite Band in Coal, One-third Actual Size . . . .10 

4. Simplified Flow Sheet, »Pyrite-Coal Concentration.19 

5. Outline of Treatment of Raw Pyrite Showing Balance of Various Prod¬ 

ucts and Accounting for Sulphur.21 

6. Outline of Further Treatment of Jig Middlings, Showing Balance of 

Products.22 

7. Gyratory Rock Breaker in University of Illinois Mining Laboratory 

(Machine Marked with a Cross).25 

8. Housing in which Revolving Screen is Contained, with Bins Underneath. 

University of Illinois Mining Laboratory.26 

9. Trommel Screen with Lifters, Equipped as a Disintegrating Screen . . 28 

10. Harz or Luhrig Plunger Jig. University of Illinois Mining Laboratory 29 

11. Laboratory Ore Concentrating Table, One-half Commercial Dimensions . 30 

12. The Door Continuous Thickener (Patented) Installed in Steel Tank . 33 


13. Plan of Proposed Pyrite Washing Plant.36 

14. Side Elevation of Proposed Pyrite Washing Plant.37 


3 









































THE UTILIZATION OP PYRITE OCCURRING IN ILLINOIS 

BITUMINOUS COAL 


An outline of laboratory experiments performed on a commercial scale in the mining 
laboratory of the University of Illinois with a view of developing a simple process for the 
economic recovery of the pyrite (sulphur) occurring with Illinois bituminous coal and now 
commonly rejected as worthless. 


Introduction 

The mineral pyrite (or probably its true name is marcasite) 
occurs in nearly all Illinois coals as characteristic brassy yellow col¬ 
ored streaks, thin plates, lenses, nodules, bands, or balls of all sizes, 
sometimes up to 10 or 12 inches in thickness. In the ordinary course 
of mining pyrite is rejected as a deleterious impurity. Its presence 
in the coal in any considerable quantity not only affects the appear¬ 
ance and consequently the salability of the fuel, but when burned, 
pyrite promotes the formation of clinkers. Its heating value is small, 
and the sulphur dioxide gas formed from its combustion, in combi¬ 
nation with water vapor, forms an acid which tends to corrode boiler 
flues and stacks. 

Pyrite when pure contains more than 50 per cent of sulphur, 
and when the nearly pure mineral is properly burned or roasted, the 
sulphur dioxide gas resulting forms the basis for the manufacture 
of sulphuric acid. In normal times the commercial supply of sul¬ 
phuric acid is obtained as a by-product of the roasting and refining 
of zinc, lead, or copper ores which contain sulphur. The prohibition 
against undue atmosphere pollution in the neighborhood of zinc, 
lead, or copper smelters due to the formation of sulphur dioxide and 
its discharge into the atmosphere, has often made its recovery a mat¬ 
ter of necessity not regulated entirely by market demands for the 
resulting sulphuric acid. 

In normal times in the United States, the market for pyrite has 
been irregular and has been limited to small areas near the points of 
production and utilization owing to the fact that high freight rates 
have operated against extensive distribution. Moreover Spanish 
pyrite has normally been imported easily and cheaply to the extent 


5 




6 


ILLINOIS ENGINEERING EXPERIMENT STATION 


of a million tons or more per year, usually in vessels which would 
otherwise return to America in ballast. In normal times also con¬ 
siderable crude sulphur has been available for the manufacture of 
sulphuric acid. All of these factors have affected the general market 
to such an extent that the commercial demand for pyrite which might 
be recovered during the mining and preparation of Illinois coal has 
been uncertain. Moreover, since the pyrite must be freed of adhering 
coal and refuse before shipment, the extra cost of this process has 
been an added disadvantage in the normal close competitive market. 

In 1915, according to the report of the United States Geological 
Survey, 964,634 long tons of pyrite were imported while the domestic 
production was only 394,124 long tons, or about 29 per cent of the 
consumption. Of the domestic pyrite, 14,849 long tons are credited 
to Illinois, all of which, except a small amount from the northwestern 
part of the state, came as a by-product of the coal industry. Of this, 
possibly 12,000 tons came from one plant in the Danville district. 
In general then, little attention has been paid to the recovery of 
pyrite by the coal producers of the state. 

Since the beginning of the European war new conditions have 
arisen. The supply of Spanish pyrite has been largely cut off, 
and under present market conditions (July, 1917) a clean pyrite 
product is worth from three to four times as much per ton as the 
coal with which it occurs. Sulphuric acid is used extensively in the 
manufacture of explosives as well as in the preparation of fertilizers, 
and the great increase in the demand for these products coupled with 
the reduction of the supply has advanced the price to a point which 
seems to present new possibilities in connection with the recovery 
of pyrite from Illinois coals. Some coals contain so large an amount 
of pyrite that its utilization under present conditions seems commer¬ 
cially practicable, and at certain mines the refuse piles contain 
large quantities accumulated from the picking belt at the tipple, 
from hand picking in the railroad cars, or from the coal washeries. 
It even seems probable that high sulphur coals could be crushed 
and washed to advantage, but with a view of saving the contained 
pyrite rather than of obtaining a cleaner coal. Although at present 
there is an almost unlimited demand for pyrite, it should be remem¬ 
bered that market conditions may change and, with the amount of 
pyrite available at most mines, large and expensive plants are prob¬ 
ably not warranted. It becomes necessary, therefore, to design and 


THE UTILIZATION OF PYRITE IN ILLINOIS COAL 


7 


to install small plants which will free most of the pyrite from the 
coal adhering to it and will otherwise treat it to make it acceptable 
as a commercial product. Through the kindness of W. G. Hartshorne 
of Danville, the Mining Engineering Department of the University 
of Illinois has been able to secure several lots, each of about one ton, 
of crude hand-picked pyrite mixed with its adhering coal. Experi¬ 
mental work in the laboratories has been conducted with a view of 
obtaining pyrite clean enough for the market and also coal as a 
by-product, clean enough to pass as ordinary tipple screenings. The 
experiments were performed as regular class ore-dressing experiments 
by senior students in the department of Mining Engineering under 
the direction of the writer, and approved compilations from these 
results have been used to supply part of the data to be outlined. 
The possible commercial use at the present time of these results by 
the mining industry was suggested by F. W. DeWolf, Director of the 
Illinois State Geological Survey. 

Attention is called to the fact that the process outlined in this 
circular has not been developed with the ordinary small laboratory 
or hand apparatus. The mining laboratory of the University of 
Illinois is equipped with machines which are of commercial charatcer 
and which differ from commercial machines only in being in most 
cases of half their dimensions. It is thought, therefore, that the 
results of these experiments are applicable directly to a commercial 
plant, and it is with the hope that the information acquired may 
prove beneficial to the coal mining and allied industries that it is 
published. 


I. Occurrence and Nature of Pyrite in Coal 

1. Composition of Pyrite .—Any one who has examined lumps of 
bituminous coal closely or who has been underground in bituminous 
coal mines has observed the brassy yellow nodules, bands, or lenses 
which occur in the coal and which by the miners are usually called 
“sulphur,” “sulphur balls,” “cat faces,” “kidney sulphur,” or 
“brasses,” depending upon the locality and upon the particular 
shape of the mineral. Commercially, the mineral is known as Pyrite, 
Pyrites, Iron Pyrites, or Iron Sulphide. When pure it contains 
46.6 per cent of iron and 53.4 per cent of sulphur. The chemical 


8 


ILLINOIS ENGINEERING EXPERIMENT STATION 


symbol is FeS 2 . Another mineral of the same composition is Mar- 
casite. This mineral has the same chemical composition as pyrite 
but differs from it in crystallization, and often in being a little lighter 
in color and in having different cleavage or breaking angles. Marca- 
site as a rule is more readily decomposed than pyrite and is usually 
of slightly less specific gravity. As a matter of fact, it is probable 
that most of the mineral called pyrite or sulphur and found in Illinois 
coal is in reality marcasite, but as the term pyrite is applied to it 
generally, this term will be used in this discussion. 

2. Pyrite in Illinois Coals .—Sulphur in coal occurs in several 
different forms. The total sulphur content of Illinois coal ranges 
from 1 to 6 per cent. Of this a small amount, probably from *4 to 
% per cent of the coal appears in some organic combination which 
is not well understood—probabty with the hydrogen and carbon of 
the coal. Such organic sulphur is supposedly burned completely in 
the process of combustion. This form of sulphur is present in all 
coals and is so intimately combined in the coal substance that it is 
not apparent to the eye and cannot be mechanically separated from 
the coal. Such organic sulphur does not lessen the value of a coal 
for combustion. 

A small and varying amount of sulphur in coal is combined in 
the white mineral occasionally seen as flakes along the partings or 
planes of the coal. This is calcium sulphate or gypsum 
(CaS0 4 2H 2 0). Many Illinois coal beds contain small percentages 
of this impurity, and seams No. 1 and 7 in places contain consid¬ 
erable amounts. The presence of sulphur in this form is of chemical 
interest only; it usually amounts to only a small fraction of one per 
cent of the coal. 

The third general form in which sulphur occurs in the coal is as 
pyrite. Pyrite often is found in the coal in thin flakes of knife-edge 
thickness, occurring in vertical cleavage planes. This is especially 
noticeable when the coal is freshly broken. This form of pyrite 
may amount to several per cent of the total coal, but owing to its 
fine state of division, its brittleness, its thinness, and its tendency to 
adhere to the coal substance, it cannot be separated readily from the 
coal. Of greater commercial value is pyrite which occurs in the coal 
in the form of bands, lenses, nodules, or balls ranging up to several 
inches in thickness and often to several feet in lateral dimension. 



Fig. 1. Pyrite Lense in Illinois Coal 











Close View of Pyrite Band in Coal, One-Third Actual Size 


Fig. 3. 





THE UTILIZATION OF PYRITE IN ILLINOIS COAL 


11 


Fig. 1 shows a typical pyrite lense from Illinois coal. Fig. 2 shows 
a closer view of a pyrite lense in coal and gives an approximate idea 
of the size in which it occurs. Considerable foreign carbonaceous 
material can be distinguished as intergrown or streaked through the 
lense. Fig. 3 is a close view of a typical band of nearly pure pyrite 
interbedded with and adhering to the coal. 

On mining, the sulphur balls or bands, being brassy yellow in 
color and of more than three times the weight of the coal are usually 
distinguishable by the miner and are thrown into the waste or gob 
underground and discarded. Frequently pieces of pyrite are more 
or less covered with adhering coal and if missed by the miner may 
be removed by hand picking in the tipple or on the railroad cars 
at the surface. It does not pay to attempt to free all the coal adher¬ 
ing to the discarded lumps of pyrite, especially as they must be 
hammered or knocked off by hand. Consequently pyrite lumps 
derived from hand-picking the coal always have some adhering coal. 

3. Origin of Pyrite .—The origin of pj^rite in coal has been the sub¬ 
ject of some speculation. With reference to this, it is to be noted that 
underground circulating waters may contain considerable amounts of 
iron salts, hydrogen sulphide, and gypsum and other salts in solution, 
which will deposit or precipitate under favorable conditions. Such 
conditions are furnished by the reducing tendencies of the carbon¬ 
aceous matter in the coal and by the more porous layers of the seam 
which furnish easy channels of circulation for the solutions. The 
firmer bands of the seam tend to define and to limit these channels. 
Deposition having started around some favorable nucleus, further 
deposition tends to enlarge the particle. When the solution contains 
iron and sulphur compounds, the final result will be nodules, bands, 
or lenses of pyrite. Less resistance usually has been offered to the 
growth of these masses along the bedding or lamination planes of the 
coal than in other planes. For this reason pyrite bands are horizontal 
in the bed and may be either flat or slightly lenticular in shape. 
Often the bands are as much as one or two inches in vertical thick¬ 
ness, and they may have a horizontal area of many square feet. The 
lenses are sometimes 5 or 6 inches in the vertical dimension and con¬ 
siderably greater in the lineal dimension along the bed. Occasionally 
lumps of pyrite are seen, the forms of which suggest the replacement 
of bits of branches or other woody tissues. 


12 


ILLINOIS ENGINEERING EXPERIMENT STATION 


That at least a part of the sulphur in coal is not due to reduction 
and deposition from circulating waters has been suggested editorially 
by Coal Age (Aug. 23 and Oct. 18. 1913). In general all vegetable 
life requires and contains the element sulphur combined in the form 
of sulphates. Recent analyses have shown the amount contained 
to be far greater than was formerly supposed. Since sulphur was 
probably contained in the vegetable matter forming the coal substance 
and since certain bacteria have the power of extracting sulphur from 
sulphate, it is reasonable to ascribe such a biochemical origin to at 
least part of the sulphur found in coal. 

From this discussion it will be seen that an analysis of the total 
amount of sulphur in coal need not give a complete measure of the 
amount of pyrite which may be recovered. Those forms of sulphur 
which are organically combined, those which occur as gypsum, or 
those which occur in the very thin leaves or plates of pyrite are not 
recoverable. Only that form of sulphur‘occurring as pyrite lumps 
of fair size can be recovered by a washing process. 

4. Recovery of Pyrite .—Up to the present time in Illinois only 
occasional efforts have been made to separate the pyrite from the ad¬ 
hering coal and to recover it in a condition clean enough to warrant 
marketing. At one mine in the Standard (Belleville) district at 
which seam No. 6 is worked, enough of this lump pyrite is picked in 
a clean condition from the coal during screening and loading to 
justify saving, and, in the past, shipments of the product separated 
by hand from the adhering coal have been made to various chemical 
companies for use in the manufacture of sulphuric acid. At certain 
mines in the Danville district, seam No. 7, numerous large bands 
of pyrite are hand-picked from the coal either by loaders under¬ 
ground or by pickers in the tipple during screening and cleaning. 
Several mines in this district are open-cut or stripping mines, and 
opportunity is thus offered for the removal of the pyrite from the 
coal during loading in daylight when the glistening yellow metal is 
easily detected. 

Enough impure pyrite is being secured from several mines to 
justify the operation of washing, jigging, or dressing plants in which 
the raw pyrite with its adhering coal is crushed and washed. After 
the completion of this process the clean pyrite is shipped and a quan¬ 
tity of fairly clean coal screenings is recovered as a by-product. The 


THE UTILIZATION OF PYRITE IN ILLINOIS COAL 


13 


pyrite washery near Danville* probably treats more than 100 tons 
of the impure pyrite with its adhering* coal, per 10-hour day. Of this 
amount, somewhat more than 50 per cent is recovered as clean pyrite, 
and most of the remainder is recovered as coal. 

5. Market Conditions .—To meet the demands of chemical com¬ 
panies which purchase pyrite, a certain degree of purity is necessary. 
Perfectly pure pyrite should contain 53.4 per cent of sulphur and 
46.6 per cent of iron. Since the sulphur is the valuable component 
in pyrite, buyers generally specify that the finished product must 
contain at least 40 per cent of sulphur, and contracts are often exe¬ 
cuted on the basis of a minimum of 44 per cent. The specifications 
of some chemical companies also limit the maximum of carbon that 
may be contained in the pyrite to 8 per cent. Roughly, this means 
about 16 per cent of contained coal. It may be seen, therefore, that 
pyrite must be freed of practically all of its adhering coal in order 
to pass this test. The pyrite found in Illinois coal even when appear¬ 
ing perfectly clean does not analyze 53.4 per cent sulphur, as there 
is some impurity, probably carbon, generally combined or intimately 
mixed with it; thus a lump of apparently absolute purity would 
probably analyze about 50 per cent sulphur. A second requirement 
of the buyers in the past has been with reference to size. Lump or 
broken pyrite, greater than 2-inch ring size, has generally brought a 
higher price per unitf than pea pyrite or pyrite ranging in size 
from 2 inches down to about *4 inch or % inch, and this also has 
general^ been worth more than the fines or pyrite below *4 inch. 
In fact the fine material has often been unsalable. Within the last 
3^ear or two, specifications as to size have changed. The development 
of new furnaces in which the raw pyrite is burned or roasted has 
made fines more desirable than lump. The demand for fines has also 
been increased by the development of certain uses for which the iron 
cinder or residue from the fines can be utilized. 


*This plant is described in an article by C. M. Young in COAL AGE, Vol. XI, No. 1, 
p. 9, Jan. 6, 1917. 

t By price per unit is meant the price per per cent, of sulphur. Thus, if a pyrite 
contains 40 per cent of sulphur and the price is 10 cents per unit, 40 times 10, or $4.00, 
is the price per ton of the material. In the same way pyrite having 45 units, or 45 per cent 
of sulphur is worth $4.50 per ton. It generally pays, therefore, to prepare and ship 
the highest grade product, providing, of course, that in preparation, the losses of material 
are not greater than the benefits to be gained. 



14 


ILLINOIS ENGINEERING EXPERIMENT STATION 


While no definite prices per ton for the different sizes can be 
quoted owing to the changing market conditions, information received 
from what are believed to be reliable sources states that the present 
market price (July, 1917) for pyrite is as high as 20 cents per unit, 
f. o. b. point of production, and the belief is expressed that the price 
will not be lower than 15 cents per unit during the next two years. 
This compares with a former price of 10 cents per unit ruling two 
years ago. Twenty cents per unit equals $8.00 per ton if the pyrite 
contains 40 per cent of sulphur, or more than four times the value per 
ton of the coal at the mine. 

There are many mines in Illinois at which considerable pyrite 
is thrown into waste or gob underground, or is discarded at the 
picking belt at the surface. Through the agency of the Illinois Co¬ 
operative Coal Mining Investigations many analyses are available 
showing the amount of sulphur contained in Illinois coals. These 
indicate that face samples taken underground have a sulphur content 
ranging from less than 1 per cent to more than 6 per cent, of which 
amount probably 60 to 90 per cent is combined in the form of pyrite. 
The directions given the samplers in this work called for “the exclu¬ 
sion of sulphur bands or balls above % inch in thickness or of thinner 
ones if, in the judgment of the sampler, these are excluded by the 
miner in loading his coal.” It is evident that these “excluded” bands 
comprise the important product from the standpoint of pyrite recov¬ 
ery. For this reason no sulphur analyses of face samples are pre¬ 
sented herein. 

Considerable quantities of pyrite might be recovered in many 
parts of the state, particularly in seams Nos. 1 and 2 in the north¬ 
western part, in the LaSalle district where seam No. 5, or the “second 
vein” coal, is worked, in seam No. 6 in the Belleville and Staunton 
districts, in seam No. 5 in the Harrisburg district and in seam No. 7, 
where mined (usually in the Danville district). At the present time 
the demand is so great that some mines are shipping the hand-picked 
pyrite without further cleaning, even though its content of sulphur is 
not so high as 40 per cent. Chemical companies, however, are buying 
this material at a reduced price per ton. 

At the present time in Illinois there are about twenty-five coal 
washeries producing clean coal. The refuse from these waslieries 
contains from about 4 to more than 22 per cent of sulphur, generally 
in the form of pyrite lumps. 


THE UTILIZATION OF PYRITE IN ILLINOIS COAL 


15 


In contrast with some pyrite derived from other sources, the 
pyrite from Illinois coal contains no arsenic or antimony, impurities 
which sometimes impair an otherwise salable pyrite. Illinois pyrite 
also burns and decomposes easily. On the other hand, any consider¬ 
able percentage of carbon or coal in the material causes the gas to 
be smoky and the resultant acid to be dirty. Modern methods of 
scrubbing or cleaning the gas have partially overcome this difficulty. 
The tendency of the Illinois pjrrite to oxidize and decompose readily 
is a factor which does not permit of storage for any considerable 
period. Certain pyrite from other sources contains some copper 
which may be recovered after burning, thus adding to its value per 
ton. 

6. Pyrite in Refuse Heaps .—Table 1 shows the percentages of 
sulphur in several of the waste heaps at Illinois washeries, and also 
that in the refuse from several tipple picking belts. Some of the 
washeries have been running for years and have accumulated large 
heaps or dumps of the refuse. The possibility that these might 
profitably be retreated at the present time to recover their pyrite 
content is worthy of consideration. Should the present market con¬ 
tinue, the probability of profitably washing high pyrite coals with a 
view of producing pyrite rather than of benefiting by the added value 
of the washed coal can be given serious attention. It is a fact that 
certain mines in Illinois have been abandoned owing to the high 
pyrite content of the coal. The possibility of reopening such mines 
as pyrite producers, at the same time recovering the coal as a by-prod¬ 
uct, is a subject which can be considered at this time. 

7. Oxidation of Pyrite .—The pyrite obtained from Illinois coal 
oxidizes or weathers very rapidly on exposure to the air. Within a few 
days after mining, a white salt may be noticed on the surface of the 
lumps. This white salt is iron sulphate, FeS0 4 , and is the product of 
the absorption by the pyrite of oxygen from the air. Thus, if exposed 
for any length of time, the pyrite tends, at least on the surface, to 
become oxidized and to the extent of such oxidation to be rendered 
valueless. Pyrite masses in heaps which have the appearance of 
being oxidized, if examined closely, will often be found to have been 
affected only at the surface, and what may seem to be a mass of 


16 


ILLINOIS ENGINEERING EXPERIMENT STATION 


Table 1 1 

Amount of Sulphur and Pyrite in Refuse of Coal at Various 
Illinois Coal Preparation Plants 


Seam 

No. 

Plant 

Situation 

Character of Material 

Percentage 
of Sulphur 

Percentage 
of Pyrite 
in Material 2 

2 

Washery 

Northern Field 

Washery Refuse 

9.35 

16.83 

2 

Washery 

Northern Field 

Washery Refuse 

22.01 

39.62 

2 

W ashery 

Northern Field 

Washery Refuse 

8.06 

14.51 

2 

W ashery 

Northern Field 

Washery Refuse 

4.57 

8.14 

2 

Washery 

Northern Field 

Washery Refuse 

5.27 

9.49 

2 

Washery 

Northern Field 

Washery Refuse 

6.77 

12.19 

2 

Washery 

Northern Field 

Washery Refuse 

4.21 

7.58 

6 

Washery 

Central Field 

Washery Refuse 

16.55 

29.79 

6 

Washery 

Central Field 

Washery Refuse 

12.57 

22.63 

6 

Washery 

Central Field 

Washery Refuse 

22.45 

40.41 . 

6 

Washery 

Southern Field 

Washery Refuse 

10.42 

18.76 

6 

Washery 

Southern Field 

Washery Refuse 

4.34 

7.81 

6 

Washery 

Southern Field 

Washery Refuse 

13.67 

24.61 

6 

Washery 

Southern Field 

Washery Refuse 

10.03 

18.05 

6 

Washery 

Southern Field 

Washery Coarse Refuse 

10.25 

18.45 

6 

Washery 

Southern Field 

Washery Fine Refuse 

10.03 

18.05 

6 

Tipple 

Southern Field 

Picking Belt Refuse 
Hand-Picked 

4.84 

8.71 

6 

Rescreener 

Southern Field 

Hand-Picked 

6.60 

11.88 

5 

Tipple 

Southern Field 

Hand-Picked 

12.00 

21.60 

7 

Mine 

Danville 

Hand-Picked 

50 tons crude pyrite hand¬ 
picked from 1,000 tons 
coal 


1 Washery results from “Coal Washing in Illinois,” by F. C. Lincoln, Univ. of Ill. Eng. Exp. Sta., 
Bui. 69, 1914. 

2 Assuming 90 per cent of sulphur is in pyrite form and that this is 50 per cent sulphur. 


powdery white iron sulphate will in reality be found to be a lump 
of solid pyrite with onty a coating of the sulphate. This coating 
(FeSOJ especially when freshly formed is soluble in water and 
should be easily removed during the washing or cleaning process. 

Washed pyrite when stored immediately may heat slightly while 
drying. Experience has shown, however, that pyrite will not tire 
if it is comparatively pure and does not contain considerable coal, 
bits of wood, or other easily ignitible material. 


































THE UTILIZATION OF PYRITE IN ILLINOIS COAL 


17 


8. Description of Machinery used in Preparing Pyrite and Out¬ 
line of Washing Tests .—Owing to the uncertainty of the market con¬ 
ditions, "any installation for the purpose of recovering pyrite, espe¬ 
cially if only a few tons per day of mixed pyrite and coal are to 
be recovered, must be simple in character, of low cost, and capable of 
being operated by unskilled labor. It is believed possible for several 
mines in a district to co-operate, if necessary, in the erection of a 
small plant of a character similar to the one hereinafter described. 

Since the hand-picked pieces of pyrite from coal range up to 
several inches thick and more than a foot square, and since pieces of 
coal tend to adhere to the lumps, hand-picking in general will not 
produce a high grade product. It is true that by hand-picking and 
hammering the larger lumps may be freed of coal sufficiently to 
produce a salable product, but this method involves the waste of the 
large amount of pyrite which occurs in pieces smaller than 2 inches 
in diameter, or of a size too small to permit hand-picking to be done 
profitably. It should be remembered also that the fine pyrite is of 
greater value per ton than the coarse material. 

Since the specific gravity of the pyrite is high (4.7 to 5.1) as 
compared with that of coal (1.3), washing by a process involving 
jigging or agitation in water causes the heavy mineral to sink rapidly 
while the light material may be drawn off at the top. This principle 
of separation is used in the ordinary jig. 

With the purpose of devising some simple washing or ore-dressing 
process to effect a separation of the pyrite from its adhering coal, 
the Department of Mining Engineering of the University of Illinois 
has undertaken a series of tests with various samples of pyrite. As 
a result of these experiments an arrangement of machines has been 
worked out, and the power required and the cost of operation have 
been determined for a simple plant capable of preparing nearly pure 
pyrite on the one hand and commercial coal on the other. 

The mining laboratory at the University of Illinois is equipped 
with rock crushers, breakers, and rolls of several different kinds in¬ 
stalled in such manner as to make possible the determination of the 
best method or crushing any ore or coal to the size necessary for sub¬ 
sequent treatment. With this equipment are screens of the revolving 
or trommel type, and shaking and vibrating screens to divide 
the crushed material into the several sizes required for further 
treatment. There are also jigs of the plunger, Harz, or Luhrig type. 


18 


ILLINOIS ENGINEERING EXPERIMENT STATION 


and jigs of the basket or Stewart type. These jigs separate the valu¬ 
able mineral from the refuse. In addition special machines in the 
form of concentrating tables are installed for special treatment of 
fine or small material, that is, material too small to be successfully 
handled by jigs. 

Preliminary tests were made by crushing the crude pyrite to vari¬ 
ous sizes in different types of crushing machinery such as breakers, 
rolls, and pulverizers, and by comparing the various samples of 
pyrite to determine the extent to which separation of pyrite and 
coal had been effected. Sizing tests were made on various kinds of 
screens and separation of these products was effected by different 
types of jigs, washers, and concentrating tables. The Delamater float 
and sink test machine was particularly useful in determining roughly 
the possibilities of separation of various sizes of mixed coal and 
pyrite. The possibility of separating pyrite from coal by a strong 
electric magnet was also tried, but under the influence of a 6-ampere 
40-ohm electric magnet installed in a Dings electromagnetic separator, 
the results were negative. Without describing in detail the various 
tests, it is sufficient to give an outline and to present the average 
results of those tests which proved most successful, and which the 
writer is convinced give a high percentage of recovery at a low 
or reasonable cost. 


II. Summary of Tests 

9. Machinery Required .—The tests performed lead to the con¬ 
clusion that the practical separation of pyrite from Illinois coal for 
the purpose of obtaining a commercial grade of pyrite, with coal as 
a by-product, presents no difficulty when performed by crushers, 
screens, and concentrating machines adapted to ordinary ore-dress¬ 
ing work. The chief problem is to secure a plant of the greatest 
simplicity and of the lowest cost. At the same time it should be of 
good capacity and should yield a high percentage of recovery of the 
pyrite. 

10. Percentage of Recovery .—The experiments from which the 
data are to be detailed indicate that a simple plant will recover about 
81 per cent of the pyrite in the coal, and that if the middlings product 
from the jig is crushed and retreated, this recovery can be increased 


THE UTILIZATION OF PYRITE IN ILLINOIS COAL 


19 


Hand pickedpyrife 


Sow crusher 


T 


Wafer 

zq" 


'1 


t 


t/evafor 


~lf j f 

Disintegrating screen (// ) 

r ^ 

Unders/ze Oi/erslze \ 

■ 

* y 


g from met screen 

u 

Oyer (jfto ig) 

“Tr 

/%7/"2 y/^7 


1_ 


Tailings 


Concenfrafes 


C/ean coarse 
-, pyrite 

i Heady for shipment. 

Under (J) 

-7f 

W/tffey fah/e 

~r i 

Tailin gs Concenlrales 


Middling s 


Rolls fo g 


J 


C/ean coal (Ready 

Screenings s/zej for use) 


(Ready C/ean fine 

pywte. 


T 


C/ean coa if Ready i I C/ean medium 

w°s nut (for use) ^ pyrife 

l)f?eady for shipment,9 


)p)fer_ sejf/ernent _ 

^ 1 

Sfudge (to waste) 


C/ear wafer 


\ 


_I 


Fig. 4. Simplified Flow Sheet, Pyrite-Coal Concentration 
















































20 


ILLINOIS ENGINEERING EXPERIMENT STATION 


to about 87 per cent. This pyrite will average more than 40 per cent 
of sulphur and may be sold directly to chemical or to fertilizer com¬ 
panies. The coal recovered as a by-product is not greatly inferior to 
ordinary screenings. 


Table 2 

Estimated Operating Statement of a Pyrite Plant of a 
Capacity of 50 Tons per 8-Hour Day 


Debit 


50 tons of Hand-Picked Pyrite at 
$1.35 . 

Interest and Depreciation on Plant 
Investment of $18,000 at 20 per 
cent per year. 


Credit 


$ 77.50 


Coarse Pyrite 24,000 lb., 45 per cent 
Sulphur at 15 cents per unit =$0.75 
per ton. 


12.00 


Pea Pyrite 22,000 lb., 45 per cent Sul¬ 
phur at 15 cents per unit . 


81.00 


74.25 


Labor, 5 men at $3.00.15.00 

Supplies and Renewals . . . . 15.00 

Power, 50 H.P.10.00 


Fines 6,510 lb., 41 per cent Sulphur at 

15 cents per unit.20.02 

Extra Pyrite if Middlings are retreated 

=4,290 lb., 43.5 per cent Sulphur . 13.99 


' $129.50 


Coal 35,231 lb. at $1.00 per ton . . 17.62 

Loss (allowing for coal in middlings 
as loss) 8,325 lb. 


$206.88 
129.50 


Profit per day.$ 77.38 

Profit per ton of raw pyrite . . . $ 1.55 


11. Estimated Operating Result .—An effort has been made to 
forecast the results of operating a 50-ton per 8-hour day pyrite plant, 
under conditions comparable to the average to be met at Illinois 
mines where pyrite is to be found in sufficient quantities to warrant 
recovery. The summary presented in Table 2 is based partly upon 
estimated figures, especially with reference to the cost of crude pyrite 
as laid down at the plant. The figures given for the value of the 
product are based on a price of 15 cents per unit of sulphur. The 
capital cost of the plant will be found detailed on page 40. In nearly 
every case, the estimates are believed to represent maximum costs 
and conservative selling prices. 

12. Method of Operation. —Fig. 4 is a diagrammatic illustration 
or simplified flow sheet of the treatment plant recommended as a 
result of the tests performed. The successive steps believed essential 
















THE UTILIZATION OF PYRITE IN ILLINOIS COAL 


: 21 


to the complete treatment of such pyrite are shown. Fig. 5 shows the 
same flow sheet with percentages of recovery attained at each part 
of the process. This indicates results which might be accomplished 
in practical work. Owing to the difficulty experienced in regulating 
machines for the relatively small tonnage treated in laboratory work, 
it is believed that in every case, commercial practice on a large scale 


Raw pyr/te 

50 tons {per Q hour c/a y 
Crushed and screened 


Less than y /nch diem. 
P/nes 

/OS tons 2) % 

2/, OOO fb 


- ] 

More than /]inches darn. 


Coarse pyr/fe 
/2 tons 24% 
45.47, su/phur 
/OQ9G /b su/phur 


f 


Pyr/fe [Concentra/es) 
J/ % 
<25/0 /b 


41.05 7 su/phur 
2672/b su/phur 


—[ i 

Coa/ Losses 

63% <2% 

/323/ /h 1260 /fa 

3./7 su/phur 6./% su/phur 
/OG/ /b su/phur /02/b. su/phur 

Z7% ash 


/Vfed/um s/zes 
£' to /f ; nch 
27.5 tons 55 % 

55000 /b 

I 

Midd//nas Ta/t/ngsCCoa/J Losses 
/5% 40% 5% 

3250/b 22,000/b 2750/b 

27.4Z su/phur 8.3 % su/phur 3.3 % su/phur 

3922 lb su/phur 22GO /b su/phur /82G/b. su/phur 238/b su/phur 

/77o ash / 7 % ash 


\ 


Pyr/te [Concentrates] 
40% 
22000/b 
45./ 7, su/phur 


' t 

5ee Rp C 

Fig. 5. Outline of Treatment of Raw Pyrite Showing Balance of Various 

Products and Accounting for Sulphur 


















22 


ILLINOIS ENGINEERING EXPERIMENT STATION 


would result in higher recovery than is indicated by this outline. The 
tonnage is based on a plant capable of treating 50 tons of crude 
hand-picked pyrite per 8-hour da3 r , as this is believed to represent 
the largest plant needed by one mine or even by several mines com¬ 
bined. 


dig middlings (Mixed coo/one//oyr/tej 

6250 /b 
27.4- % su/phur 
22G0 /b su/phur 

r~ 


Crush io / in roi/s 


U 

Pyrite 
52 % 

4290 /b 
435Z su/phur 
/QGG it su/phur 


Coai one/ /oss 
43 Z 


Coo/ 3530/b 
3.2 % su/phur 
325ib. su/phur 
/77o ash 


Loss 

5u/phur no/ 
accounted for 
GS ib 


Coo/ /oss 
3// ib 

3Z of /be coo/ 


Fig. 6. Outline op Further Treatment of Jig Middlings, Showing 

Balance of Products 


Fig. 6 is a diagram which indicates the possibilities of recrushing 
the middlings product obtained from the second compartment of the 
jig, then screening it through the % inch trommel screen, and allow¬ 
ing it to pass either to the jig or to the concentrating table, according 
to its size. In this way the recovery can be increased by about 6.4 
per cent. 















THE UTILIZATION OF PYRITE IN ILLINOIS COAL 


23 


Table 3 shows the amount and percentage of recovery or loss 
of the pyrite in each operation of the process, based on sulphur con¬ 
tent as determined by sampling and by analysis of each of the 
products recovered. 


Table 3 

Flow Sheet Reduced to a Basis of Sulphur Content, Showing the Amount 
of Sulphur in Each Product Based on the Output of a Plant 
Having a Capacity of 50 Tons per 8-Hour Day 


Product 

Name 

Size 

Sulphur 
Per Cent 

Sulphur 

Content 

Lb.l 

Sulphur 

Recovered 

Lb. 

Per Cent of 
Total Sulphur 
Recovered 
or Lost 

Coarse (Screen) 
Concentrates 

Lump 

Pyrite 

Above 1M in. 
ring 

45.4 

10896 

10896 

37.6 

Fine (Table) 
Concentrates 

Fine 

Pyrite 

Under in. 

41.05 

2672 

2672 

9.2 

Medium (Jig) 
Concentrates 

Pea 

Pyrite 

l}4 in. to 

U. in. 

45.1 

9922 

9922 

34.2 

Total 





23490 

81.0 

Recovery 

Middlings from 
Medium 
Concentrates 


Crushed to 

H in. 


2260 

1866 


Total with 
Middlings Added 





25356 

87.4 

Recovery 

Fine Coal 

No. 5 Nut 

Under % in. 

8.1 

1826 



Coal from Jig 
Overflow 

Screening 

Size 

1K in. to 
% in. 

8.3 

1061 



Loss (Jig) 

Coal 

Estimated 

8.3 

102 



Loss (Table) 

Coal 

Estimated 

8.1 

238 



Loss (Middlings) 

Pyrite 

Not acct. for 

69 lb. 




Total Sulphur in 
Original Product 




28977 




1 28,977pounds of sulphur from 50 tons of material amounts to 28.98 per cent of sulphur in orig¬ 
inal crude hand-picked pyrite (assuming all sulphur to be in the form of pyrite). For pyrite con¬ 
taining 53.4 per cent of sulphur, the total pyrite content of the crude pyrite would be 54,264 pounds, 
or 54.26 per cent of pyrite, and, therefore, the content of coal and contained ash and shale would be 
45.74 per cent. The total recovery from disintegrating screen, jig, and table on the crushed crude 
pyrite was 81.0 per cent of the total pyrite or 23,490 pounds of sulphur from the 28,977 pounds con¬ 
tained in 100,000 pounds of crude pyrite. If the middling product from the jig is recrushed and 
treated, the recovery is increased to 87.4 per cent, or 25,356 pounds. 


The coal produced as a by-product contains about 8 per cent of 
sulphur, a part of which is in the form of pyrite. In commercial 
operations extending over considerable periods this loss of pyrite 
could be decreased, as it is largest when starting and while shutting 
down the machinery. These operations occur frequently in experi¬ 
mental runs. The amount of coal recovered as a by-product is 































24 


ILLINOIS ENGINEERING EXPERIMENT STATION 


considerable, the tests indicating 38,811 lb. per day from the plant 
and product under discussion, or from 18 to 20 tons. It should be 
remembered that this coal is of screening size, and that its purity 
depends largely upon the care with which the pyrite is removed dur¬ 
ing the process of cleaning. 

13. The Tests and the Results .—In the final tests the pyrite as 
received (about a ton in weight) contained from 25 to 28 per cent of 
sulphur, or about 50 per cent by weight of pyrite. The other 50 
per cent of the mineral consisted of coal adhering to the lumps and 
intermixed with the bands of pyrite. The material had been hand¬ 
picked at a tipple preparing No. 7 coal in the Danville district. The 
lumps including the adhering coal were as large as 6 or 8 inches in 
thickness, and were often a scpiare foot in area. This material was 
first put through an ordinary rock breaker. The rock breaker in the 
laboratory is of the Gates gyratory type (Fig. 7), but from tests 
made with a Blake type of rock breaker it is believed that the latter 
type will be equally satisfactory and probably cheaper in first cost. 
Attention is here called to the fact that ordinary coal crushing 
machinery is not suitable for crushing raw pyrite. The pyrite is 
extremely hard and only breakers designed for hard rock should be 
used. Breakers designed for soft material do not possess adequate 
strength, and the wear will be excessive if used on this class of 
material. 

The breaker was set with a throat opening, or discharge, about 
D /2 inches wide, and although the pieces discharged through this 
had a thickness of not more than 1 y 2 inches, the area of some of the 
lumps was several scpiare inches in extent owing to the tendency of 
the pyrite to break into flat slabs. Examination showed that this 
breaking process caused a large portion of the lump pyrite to sep¬ 
arate from the adhering coal. The coal itself tended to break into 
cubical pieces. Also the coal, because of its brittleness, generally 
broke up into finer sizes than the pyrite. After breaking, the large 
lumps of pyrite had only small bits of coal adhering to them. Thus 
it was decided to screen this material in an attempt to secure a coarse 
pyrite which would be sufficiently clean for the market. 

The crushed material was put through a revolving or trommel 
screen having round hole openings of about the same diameter as 
the opening in the rock breaker. Fig. 8 illustrates the housing 



Fig. 7. Gyratory Rock Breaker in University of Illinois Mining Laboratory 

(Machine Marked with a Cross) 






















Fig. 8. Housing in which Revolving Screen is Contained, with Bins Under¬ 
neath. University of Illinois Mining Laboratory 


























THE UTILIZATION OF PYRITE IN ILLINOIS COAL 


27 


in which the revolving screen used in the experiments is contained, 
and shows it to be of commercial size. Since the coal tended to break 
into cubical pieces while the pyrite tended to break into flat pieces, 
it was thought that a separation could be made of the two by simple 
screening alone. This expectation was borne out by results obtained. 
Later, steel lifters were introduced in the revolving screen as shown 
in Fig. 9. During screening these lifters caused the material to be 
carried to the top of the screen and to be dropped several feet. The 
impact from this fall served to break any large coal so that it passed 
through the screen, and it also freed the pyrite of any small particles 
of adhering coal. It was shown also that lump pyrite may, if desired, 
be further cleaned by screening the material while wet, that is, by 
introducing sprays of water into the screen. The rubbing action of 
the wet material against the screen serves to loosen most of the 
specks of coal remaining on the coarse pyrite so that they may pass 
through the screen. The greater the diameter of the screen, that is, 
the greater the length of fall of the particles after having been lifted, 
the freer is the oversize, or clean coarse pyrite of coal impurity. 

14. The Size of Screen Holes .—As previously mentioned the 
largest size of screen opening was about a iy 2 inch round hole. The 
screen illustrated in Fig. 9 is not unlike the Bradford disintegrator 
which is in common use for cleaning coal to free it of lumps of shale, 
pyrite, sticks of wood, bits of iron, and other impurities. The result 
of this screening was the production of 21 per cent of the total amount 
treated as clean lump pyrite of iy 2 inches in minimum size, and of 
an analyzed purity which in all the tests ran more than 40 per cent 
sulphur and in some as high as 45.4 per cent. By this simple process 
of crushing and screening, it was possible to produce 47.6 per cent 
of the pyrite immediately in the form of a clean marketable product. 

The material passing through the 1 y 2 inch holes of the disinte-. 
grating screen entered a small trommel or revolving screen having 
a screen plate with holes about % inch in diameter. The purpose 
was to separate the material smaller than 1V 2 inches into two sizes, 
one of which should contain all sizes between iy 2 inches and % inch, 
and the other, all sizes below *4 inch. If desired, the same results 
could be obtained by adding an outer screen plate with % inch round 
holes to the disintegrating screen, that is, by making it a compound 
concentric screen. In the writer’s opinion, it is more satisfactory 


28 


ILLINOIS ENGINEERING EXPERIMENT STATION 



Fig. 9. Trommel Screen with Lifters, Equipped as a Disintegrating Screen 
























































































Fig. 10. 


Harz or Luhrig Plunger Jig. University of Illinois Mining 

Laboratory 






















Fig. 11. Laboratory Ore Concentrating Table, One-Half Commercial 

Dimensions 





















THE UTILIZATION OF PYRITE IN ILLINOIS COAL 


31 


to use separate screens, especially if the matter of making repairs 
easily is considered. Where all the sizes less than iy 2 inches in 
diameter were washed or jigged together, the separation of the pyrite 
from the coal was incomplete, especially in the fine sizes below about 
inch. Jigs are not well adapted for the treatment of these fine 
sizes, therefore separate treatment of the material below 14 inch should 
be made on a special concentrating table designed for fine material. 

Of the amount falling through the holes of the disintegrating 
screen, 70 per cent was larger than 14 inch. This material larger than 
14 inch in diameter and smaller than iy 2 inches was sent to a two- 
compartment Harz or Luhrig plunger jig. The jig used in the labora¬ 
tory (Pig. 10) is of the two-compartment commercial type and is of 
half dimensions, capable in every way of giving, commercial products. 
Prom this jig three products were obtained: Number 1 was a clean 
pyrite product from the first compartment draw-off which amounted 
to- 22 per cent of the total feed or 34.2 per cent of the total pyrite 
in the mineral. The sulphur content of this product ranged from 
42 per cent to 46 per cent. Number 2 was material from the second 
compartment amounting to 7.8 per cent of the total pyrite or 2.3 
per cent of the amount fed. This material was a true middling 
product; that is, it consisted of pieces of pyrite and coal which had 
not been freed from each other. In other words, the weight of any 
piece lodging here was not quite sufficient to cause it to settle in the 
first compartment, and still the piece was not light enough to allow 
it to overflow the second compartment. Number 3 was the overflow 
material from the second compartment which was found to be prac¬ 
tically clean coal. In the preliminary runs some pieces of pyrite 
were observed in this clean coal, but after a few trials to get the cor¬ 
rect adjustment of the jig, no difficulty was experienced in obtaining 
a coal comparable with the ordinary screenings furnished by Illinois 
coal mines. 

Middlings such as were noted in the second compartment were 
not in condition to be marketed since their sulphur content was only 
27.4 per cent. In commercial practice, if the quantity of these mid¬ 
dlings is sufficient to warrant it, more nearly complete separation may 
be accomplished by recrushing to a finer size and passing again 
through the disintegrating screen. 

In coal washing work in Illinois little attention has been paid to 
material under % inch, largely because material of this size usually 


32 


ILLINOIS ENGINEERING EXPERIMENT STATION 


contains an excess of refuse and because it does not readily dry out 
or free itself of water In pyrite washing, however, conditions are 
different. A considerable portion (21 per cent) of the material 
crushed in the rock breaker will be found to be under *4 inch in size. 
Since this material contains about 42.2 per cent of pyrite and since 
this fine pyrite has become more valuable than the larger sizes, some 
form of modern ore-concentrating table should be used to separate 
pyrite from coal in these sizes. No difficulty will be found in freeing 
these sizes of pyrite of water. In the experimental work, a laboratory 
concentrating table of half commercial dimensions was used. This 
table is illustrated in Fig. 11. It was made by the Traylor Engineer¬ 
ing Company of New York City, and is similar to other well-known 
makes, which include the Wilfley, Overstrom, Deister, Butchart, and 
others. The material fed to the table in the test runs was effectively 
separated into fine pyrite, containing on the average run more than 
40 per cent sulphur, and fine coal which might be added to the coal 
obtained from the jigs. As a rule, the handling of quantities of such 
fine coal presents some difficulty because of the problem of removing 
the water from it after washing. 

15. Losses .—The tests indicate either 81 or 87 per cent recovery 
of the pyrite as shown by sulphur analysis, and therefore show a loss 
of 19 and 13 per cent, respectively. This seems to be a satisfactory 
metallurgical recovery for such a washing process, especially since 
the effort has been to employ the simplest sort of machinery. 

Probably 5 to 20 per cent of the coal in the smaller sizes will 
be lost during the process, largely by passing off as sludge in the 
water. Analyses indicate that this sludge is too impure to be used 
as coal. Not only is it very fine, but much of the clay or shale 
impurity which is intermixed with the coal has softened under the 
influence of the water and passes off with the sludge. 

16. Water Supply .—In any wet concentration process using jigs 
and concentrating tables, the question of an adequate supply of 
water is important. Water is used in spraying the rock in the breaker 
for the purpose of keeping down dust; it is used in the disintegrating 
screen to assist in the cleaning; and from this point the material 
under iy 2 inches in size is practically flowing in a stream of water. 
The jig and concentrating table both require water, for the feed, for 



CLEAR 

SOLUTION 

OVERFLOW 


t&CA i A&rtO Ct “r ' 


THICK SLIME uiatnflmit 
TO PUMP OR NOZZLE 


<®t§§s 


Fig. 12. The Dorr Continuous Thickener (patented). Installed 

in Steel Tank 



























THE UTILIZATION OF PYRITE IN ILLINOIS COAL 


35 


the separating process, and for carrying away the separated products. 
By the use of perforated elevators and draining bins it is possible to 
recover all the water draining from the products in a central pond 
or sump and to use it over and over by pumping. The sediment or 
sludge in the water consists largely of fine coal and clay, since the 
pyrite is too heavy to pass off with the water except in the smallest 
sizes. The settling pond or sump common at Illinois coal washeries 
can be replaced to good advantage by a large round settling tank 20 or 
30 feet in diameter equipped with a uniformly horizontal rim over 
which the water may flow. 

The sludge water from the plant should enter this tank at the 
center and under the surface of the water. Passing toward the rim 
of the tank, the sludge will settle to the bottom and the water, suf¬ 
ficiently clean to be reused, will overflow the rim and may be directed 
into a small sump from which it may be pumped back to the plant. 
The tank should be equipped with a steeply sloping bottom so that 
the accumulating sludge may be easily removed. A settling tank of 
similar character, which has been used for many industrial purposes, 
is the Dorr settling tank illustrated in Fig. 12. The importance of 
fairly clean water in the operation of a plant of this kind may be 
readily understood since water used several times without settlement 
of the sludge often contains as much as 3 per cent of solids in sus¬ 
pension. Such water, draining from the washed pyrite, will contami¬ 
nate it by depositing solid material on its surface and will thus lower 
the sulphur percentage of a product otherwise satisfactory. 

17. Design of Plant. —Fig. 13 shows a suggested plan of a pyrite 
washing plant based on the flow sheet presented as Fig. 4. Fig. 14 
is a side elevation of the same plant. By^ following the arrows indi¬ 
cating direction of flow of the material, the operation of the plant 
may be readily understood. 

The bins, framing, and general construction material may be of 
wood or steel. Since the acid water formed through contact with 
pyrite has a corrosive action in contact with steel, it is suggested that 
at least the bin linings be of wood. At present, general wooden con¬ 
struction should be much cheaper than steel. 

In the design presented, the site has been assumed as level. If 
a sloping, or side hill, site is available, some expense for elevators 
may be avoided. In cases where elevators are required, they should 


Jetf/inq Tanfr 


ILLINOIS ENGINEERING EXPERIMENT STATION 



Fig. 13. Plan of Proposed Pyrite Washing Plant 



































































































































































































































































































































THE UTILIZATION OF PYRITE IN ILLINOIS COAL 



37 


Fig. 14. Side Elevation of Proposed Pyrite Washing Plant 




































































































































38 


ILLINOIS ENGINEERING EXPERIMENT STATION 


be of the rubber belt and steel bucket type, since these are cheaper to 
install and, for the purpose intended, will last longer than the all-steel 
types. In a small plant, bins may be omitted, and the cleaned prod¬ 
ucts may be allowed to drain on to a concrete floor, as indicated in 
Fig. 13 for fine pyrite. 

18. Cost of Plant .—The design outlined herein was submitted to 
Allis-Chalmers Manufacturing Company, Milwaukee, Wisconsin on 
July 6, 1917, with the request that they submit an estimate of the 
cost. In their reply they suggest that a disintegrating screen some¬ 
what smaller than the one illustrated in Fig. 9 should be satisfactoiy. 
With this exception, their estimates cover the design and the arrange¬ 
ment of plant as outlined in Figs. 13 and 14. The list of equipment 
and the estimates of cost as submitted by Allis-Chalmers Manufactur-' 
ing Company are as follows: 

1 ‘ 1—Blake Crusher, 15x9. 

0 

1—Disintegrating screen or trommel 48 inches diameter by 8 feet 
long having punched steel covering with 1% inch openings and 
provided with three angle iron lifters equally spaced inside the 
screen. 

1—Trommel 48 inches diameter by 8 feet long provided with punched 
steel covering having % inch round holes. 

1—Two-Compartment Harz Jig with compartments about 24 inches 
by 36 inches to be complete including iron work, wood work 
and screens. 

1—Set 18 inches by 10 inches Economic crushing rolls. 

1—Belt and bucket elevator about 35 feet long between centers 
and to be provided with top and bottom shafts, pulleys, bearings, 
driving shaft, driving gear—16-inch malleable elevator buckets 
with bolts and 18-inch 8-ply rubber belt (other elevators or con¬ 
veyors extra as needed). 

1—Overstrom concentrating table. 

1—Lot of shafting pulleys, boxes, and belting for driving the pre¬ 
viously described machinery in accordance with plans to be made. 

1—Lot of piping, valves, and fittings for water supply to the various 
machines specified but not including connections outside of 
building. 


THE UTILIZATION OF PYRITE IN ILLINOIS COAL 


39 


1—Set of drawings of plan and elevator showing the general arrange¬ 
ment of the plant will be provided with the machinery. 

‘ ‘ The price of the machinery as outlined would be $5,600.00 f. o. b. 
cars at the factory, approximate weight 42,000 lb. 

‘ 1 Shipment could be made in about 60 days from receipt of order. 

i ‘ The foregoing covers what would be practically the standard equip¬ 
ment for most of the plants, and the following details might vary with 
different installations. 

‘ ‘ 1—40 H. P. type A N. Ind. motor, 60 cycle, 3 phase, 440 V. 865 
R. P. M. for driving plant, 


Approximate weight .2,000 lb. 

Price .$550.00 


1—-Water tank for collecting waste water from plant for reuse. 
Tank would be 20 inches diameter with 10-foot staves made of 
3-inch lumber and provided with overflow launder. The capacity 
of this tank would be about 20,000 gals. 

Approximate weight .8,000 lb. 

Price .:.$300.00 

‘ ‘ This tank may seem a little large but the larger it is made the better 
will be the settling action which removes any fine coal or gritty material 
from the overflow. 

11 To return the water from this tank to the supply tank there will 
be required a pump, but probably in every case this pump would have 
to be changed to suit the conditions of the head and the quantity of water 
to be returned. It is assumed for average conditions that the pump can 
be motor driven and that a centrifugal pump will be most satisfactory 
for this service; also that a capacity of about 100 gals, per minute would 
be sufficient and that the head would be about 50 feet. 

11 2-inch type ‘S’ centrifugal pump witli direct connected motor, 
mount on base plate. The motor would be 5 H. P. Ind. motor, 60 cycle, 


3 phase, 440 volt. 

The weight of this pump would be.1,100 lb. 

Price of same.$325.00 


"No suction or discharge piping for this pump is included as this will 
have to be made to suit the conditions in each case. 

“No clear water supply tank for the plant or pump for same is included. 

11 These prices are based on the present conditions only. ’ ’ 








40 


ILLINOIS ENGINEERING EXPERIMENT STATION 


19. Summary of Capital Costs .—In the following summary the 
initial capital requirements are presented for a pyrite recovery plant 
having a capacity of 50 tons per 8-hour day as described in the fore¬ 
going paragraphs of this circular. 


General Machinery at Factory. .$5600.00 

40 H. P. Motor. 550.00 

Water Settling Tank. 300.00 

Water Pump . 325.00 


$7775.00 

or approximately $8000.00 delivered. 

If it is assumed that the installation of the machinery will cost fifty 
per cent of its original cost, or about $4000.00, including foundations, 
and that the building and bins will cost about $6000.00 (this will vary 
as to location and completeness of plant desired), the total cost of a 
complete pyrite plant capable of treating 50 tons of crude hand¬ 
picked pyrite per 8-hour day will be about $18000.00. 











THE UTILIZATION OF PYRITE IN ILLINOIS COAL 


41 


APPENDIX 

20. Analysis of Pyrite Ores for Sulphur Content .—The sulphur 
analyses listed in this circular were made according to the method 
described in Low’s “Technical Methods of Ore Analysis,” page 239, 
with the exception that it has been possible to shorten the general 
procedure somewhat since the material contains no sulphide or im¬ 
purity requiring removal. It is a simple, accurate, and practical 
method for determining sulphur in large percentages, such as are 
found in pyrite. It is presented in the following paragraphs :* 

“Treat 0.5 gram of the ore in an 8-ounce flask with 10 cubic 
centimeters of strong nitric acid. Heat very gently until the red 
fumes have somewhat abated, and then add potassium chlorate in 
small portions at a time (say 0.2 to 0.3 gram), until any free sul¬ 
phur that has separated is entirely oxidized and dissolved. The acid 
should not be boiled violently, as this would unnecessarily weaken it. 
On the other hand, it is best not to allow it simply to simmer, as the 
explosive gases from the decomposing chlorate may then collect in the 
flask and produce annoying, although not dangerous, explosions. 
When the sulphur has entirely disappeared, the solution should be 
boiled to complete dryness. This operation may be hastened by manip¬ 
ulating the flask over a free flame. After cooling, add 5 cubic centi¬ 
meters of strong hydrochloric acid. This should be done cautiously 
to avoid a too violent reaction with the undecomposed potassium 
chlorate that may be present. If iron oxide, etc., still remains undis¬ 
solved, gently heat the hydrochloric acid mixture until solution is as 
complete as possible, adding more acid if necessary. Finally, boil 
to dryness, then add 5 cubic centimeters more of the hydrochloric 
acid and again boil to dryness. This is to decompose nitrates and 
expel all nitric acid. Take up once more in 5 cubic centimeters of the 
hydrochloric acid and dilute with about 100 cubic centimeters of cold 
water. (If the solution is hot when made alkaline with ammonia, 
some basic ferric sulphate is liable to separate.) Make alkaline with 
ammonia. Heat to boiling, allow the ferric hydroxide, etc., to settle, 
and then filter and wash very thoroughly with hot water, receiving the 
filtrate in a 600 cubic centimeter Erlenmeyer flask. 


* Attention is directed to the so-called sodium peroxide method of sulphur analysis 
involving the use of a combustion bomb. This is perhaps the quickest and is also an 
accurate method for the analysis of sulphur found in ores. For a description see “Sodium 
Peroxide in Certain Quantitative Processes,” Jour. Amer. Chem. Soc., Vol. 30, 1908. 



42 


ILLINOIS ENGINEERING EXPERIMENT STATION 


“Add a drop of phenolphthalein solution as indicator, make just 
acid with strong hydrochloric acid, and then add 4 cubic centimeters 
in excess.- Dilute the solution to about 400 cubic centimeters with 
hot water, heat to boiling and precipitate the sulphur with barium 
chloride. 

“After adding the barium chloride, as described, to the boiling 
solution, allow the mixture to stand, hot, until the liquid above the 
precipitate has become perfectly clear—perhaps an hour. Filter 
through a double 11 centimeter filter. No appreciable amount of bar¬ 
ium sulphate should run through. Unless, however, the filter appears 
practically clear, always filter a second time, which will usually suf¬ 
fice. Wash the precipitate ten times with hot water. Transfer the 
moist filter and precipitate to a clean smooth 1 annealing-cup ’ and 
ignite, with free access of air, over a Bunsen burner, or in a muffle, 
at a gentle heat. A high heat, such as that of a blast lamp, is neither 
necessary or desirable. The ignited barium sulphate should be per¬ 
fectly white. Cool in dessicator, transfer to the scale-pan by tapping 
and brushing with a camel’s hair brush, and weigh. Multiply the 
weight of the barium sulphate by 0.1373 to obtain the weight of the 
sulphur. 

“A platinum or porcelain crucible may, of course, be used for the 
ignition of the barium sulphate instead of an annealing-cup. 

“It is best to run a blank, once for all, with all the reagents em¬ 
ployed, and always deduct for any sulphur thus found.” 

21. Additional Directions and Precautions .—The sulphur percent¬ 
age in barium sulphate is 13.73. 

The whole operation of solution and evaporation can best be car¬ 
ried on in a round-bottom flask over a free flame. 

It is important to keep the flask in motion constantly to avoid 
cracking, and after evaporation not to set the flask down on a solid 
substance (as a desk) until it has cooled somewhat. 

Accurate results depend largely upon the complete removal of the 
nitric acid through boiling, and for this reason the operation of 
evaporation is repeated. 

The filtering of the solution to remove the ferric hydroxide is 
hastened by allowing the precipitate to 1 settle and by decanting the 
clear solution. 

If the solution is allowed to stand for several hours, or over night, 
after adding the barium chloride, heating is usually not necessary. 


LIST OF 

PUBLICATIONS OF THE ENGINEERING EXPERIMENT STATION 


Bulletin No. 1. Tests of Reinforced Concrete Beams, by Arthur N. Talbot, 1904. None available. 

Circular No. 1 . High-Speed Tool Steels, by L. P. Breckenridge. 1905. None available. 

Bulletin No. 2. Tests of High-Speed Tool Steels on Cast Iron, by L. P. Breckenridge and Henry 
B. Dirks. 1905. None available. 

Circular No. 2. Drainage of Earth Roads, by Ira O. Baker. 1906. None available. 

Circular No. S. Fuel Tests with Illinois Coal (Compiled from tests made by the Technological 
Branch of the U. S. G. S., at the St. Louis, Mo., Fuel Testing Plant, 1904-1907), by L. P. Breckenridge 
and Paul Diserens. 1909. Thirty cents. 

Bulletin No. 3. The Engineering Experiment Station of the University of Illinois, by L. P. 
Breckenridge. 1906. None available. 

Bulletin No. 4- Tests of Reinforced Concrete Beams, Series of 1905, by Arthur N. Talbot. 

1906. Forty-five cents. 

Bulletin No. 5. Resistance of Tubes to Collapse, by Albert P. Carman and M. L. Carr. 1906. 
None available. 

Bulletin No. 6. Holding Power of Railroad Spikes, by Roy I. Webber, 1906. None available. 

Bulletin No. 7. Fuel Tests with Illinois Coals, by L. P. Breckenridge, S. W. Parr, and Henry B. 
Dirks. 1906. None available. 

Bulletin No. 8. Tests of Concrete: I, Shear; II, Bond, by Arthur N. Talbot. 1906. None 
available. 

Bulletin No. 9. An Extension of the Dewey Decimal System of Classification Applied to the 
Engineering Industries, by L. P. Breckenridge and G. A. Goodenough. 1906. Revised Edition 
1912. Fifty cents. 

Bulletin No. 10. Tests of Concrete and Reinforced Concrete Columns, Series of 1906, by 
Arthur N. Talbot. 1907. None available. 

Bulletin No. 11. The Effect of Scale on the Transmission of Heat through Locomotive Boiler 
Tubes, by Edward C. Schmidt and John M. Snodgrass. 1907. None available. 

Bulletin No. 12. Tests of Reinforced Concrete T-Beams, Series of 1906, by Arthur N. Talbot. 

1907. None available. 

Bulletin No. 13. An Extension of the Dewey Decimal System of Classification Applied to Archi¬ 
tecture and Building, by N. Clifford Ricker. 1907. None available. 

Bulletin No. 14■ Tests of Reinforced Concrete Beams, Series of 1906, by Arthur N. Talbot. 

1907. None available. 

Bulletin No. 15. How to Burn Illinois Coal Without Smoke, by L. P. Breckenridge. 1908. 
None available. 

Bulletin No. 16. A Study of Roof Trusses, by N. Clifford Ricker. 1908. None available. 

Bulletin No. 17. The Weathering of Coal, by S. W. Parr, N. D. Hamilton, and W. F. Wheeler. 

1908. None available. 

Bulletin No. 18. The Strength of Chain Links, by G. A. Goodenough and L. E. Moore. 1908. 
Forty cents. 

Bulletin No. 19. Comparative Tests of Carbon, Metallized Carbon and Tantalum Filament 
Lamps, by T. H. Amrine. 1908. None available. 

Bulletin No. 20. Tests of Concrete and Reinforced Concrete Columns, Series of 1907, by Arthur 
N. Talbot. 1908. None available. 

Bulletin No. 21. Tests of a Liquid Air Plant, by C. S. Hudson and C. M. Garland. 1908. Fifteen 
cents. 

Bulletin No. 22. Tests of Cast-Iron and Reinforced Concrete Culvert Pipe, by Arthur N. Talbot. 
1908. None available. 

Bulletin No. 23. Voids, Settlement, and Weight of Crushed Stone, by Ira O. Baker. 1908. 
Fifteen cents. 

*Bulletin No. 24. The Modification of Illinois Coal by Low Temperature Distillation, by S. W. Parr 
and C. K. Francis. 1908. Thirty cents. 

Bulletin No. 25. Lighting Country Homes by Private Electric Plants, by T. H. Amrine. 1908 
Twenty cents. 

*A limited number of copies of bulletins starred is available for free distribution. 



43 



44 


PUBLICATIONS OF THE ENGINEERING EXPERIMENT STATION 


Bulletin No. 26. High Steam-Pressures in Locomotive Service. A Review of a Report to the 
Carnegie Institution of Washington, by W. F. M. Goss. 1908. Twenty-five cents. 

Bulletin No. 27. Tests of Brick Columns and Terra Cotta Block Columns, by Arthur N. Talbot 
and Duff A. Abrams. 1909. Twenty-five cents. 

Bulletin No. 28. A Test of Three Large Reinforced Concrete Beams, by Arthur N. Talbot. 
1909. Fifteen cents. 

Bulletin No. 29. Tests of Reinforced Concrete Beams: Resistance to Web Stresses, Series of 
1907 and 1908, by Arthur N. Talbot. 1909. Forty-five cents. 

* Bulletin No. 80. On the Rate of Formation of Carbon Monoxide in Gas Producers, by J. K. Cle¬ 
ment, L. H. Adams, and C. N. Haskins. 1909. Twenty-five cents. 

*Bulletin No. 31. Fuel Tests with House-heating Boilers, by J. M. Snodgrass. 1909. Fifty-five 
cents. 

Bulletin No. 32. The Occluded Gases in Coal, by S. W. Parr and Perry Barker. 1909. Fifteen 
cents. 

Bulletin No. 33. Tests of Tungsten Lamps, by T. H. Amrine and A. Guell. 1909. Twenty cents- 

*Bulletin No. 34. Tests of Two Types of Tile-Roof Furnaces under a Water-Tube Boiler, by J. M. 
Snodgrass. 1909. Fifteen cents. 

Bulletin No. 35. A Study of Base and Bearing Plates for Columns and Beams, by N. Clifford 
Ricker. 1909. Twenty cents. 

Bulletin No. 36. The Thermal Conductivity of Fire-Clay at High Temperatures, by J. K. Clement 
and W. L. Egy. 1909. Twenty cents. 

Bulletin No. 37. Unit Coal and the Composition of Coal Ash, by S. W. Parr and W. F. Wheeler. 
1909. Thirty-five cents. 

* Bulletin No. 88. The Weathering of Coal, by S. W. Parr and W. F. Wheeler. 1909. Twenty- 
five cents. 

*Bulletin No. 39. Tests of Washed Grades of Illinois Coal, by C. S. McGovney. 1909. Seventy- 
five cents. 

Bulletin No. 40. A Study in Heat Transmission, by J. K. Clement and C. M. Garland. 1910. 
Ten cents. 

Bulletin No. 41• Tests of Timber Beams, by Arthur N. Talbot. 1910. Thirty-five cents. 

* Bulletin No. 4 The Effect of Keyways on the Strength of Shafts, by Herbert F. Moore. 1910. 
Ten cents. 

Bulletin No. 43. Freight Train Resistance, by Edward C. Schmidt. 1910. Seventy-five cents. 

Bulletin No. 44• An Investigation of Built-up Columns Under Load, by Arthur N. Talbot and 
Herbert F. Moore. 1911. Thirty-five cents. 

*Bulletin No. 45. The Strength of Oxyacetylene Welds in Steel, by Herbert L. Whittemore. 1911. 
Thirty-five cents. 

*Bulletin No. 40- The Spontaneous Combustion of Coal, by S. W. Parr and F. W. Kressman. 
1911. Forty-five cents. 

*Bulletin No. 47. Magnetic Properties of Heusler Alloys, by Edward B. Stephenson, 1911. Twen¬ 
ty-five cents. 

*Bulletin No. 48. Resistance to Flow Through Locomotive Water Columns, by Arthur N. Talbot 
and Melvin L. Enger. 1911. Forty cents. 

*Bulletin No. 49. Tests of Nickel-Steel Riveted Joints, by Arthur N. Talbot and Herbert F. Moore. 
1911. Thirty cents. 

*Bulletin No. 50. Tests of a Suction Gas Producer, by C. M. Garland and A. P. Kratz. 1912. 
Fifty cents. 

Bulletin No. 51. Street Lighting, by J. M. Bryant and H. G. Hake. 1912. Thirty-five cents. 

*Bulletin No. 52. An Investigation of the Strength of Rolled Zinc, by Herbert F. Moore. 1912. 
Fifteen cents. 

*Bulletin No. 53. Inductance of Coils, by Morgan Brooks and H. M. Turner. 1912. Forty cents. 

*Bulletin No. 54- Mechanical Stresses in Transmission Lines, by A. Guell. 1912. Twenty cents. 

*Bulletin No. 55. Starting Currents of Transformers, with Special Reference to Transformers with 
Silicon Steel Cores, by Trygve D. Yensen. 1912. Twenty cents. 

*Bulletin No. 56. Tests of Columns: An Investigation of the Value of Concrete as Reinforcement 
for Structural Steel Columns, by Arthur N. Talbot and Arthur R. Lord. 1912. Twenty-five cents. 

*Bulletin No. 57. Superheated Steam in Locomotive Service. A Review of Publication No. 127 
of the Carnegie Institution of Washington, by W. F. M. Goss. 1912. Forty cents. 


*A limited number of copies of bulletins starred is available for free distribution. 



PUBLICATIONS OF THE ENGINEERING EXPERIMENT STATION 


45 


*Bulletin No. 58. A New Analysis of the Cylinder Performance of Reciprocating Engines, by 
J. Paul Clayton. 1912. Sixty cents. 


^Bulletin No. 59. The Effect of Cold Weather Upon Train Resistance and Tonnage Rating, by 
Edward C. Schmidt and F. W. Marquis. 1912. Twenty cents. 


*Bulletin No. 60. The Coking of Coal at Low Temperatures, with a Preliminary Study of the 
By-Products, by S. W. Parr and H. L. Olin. 1912. Twenty-five cents. 


* Bulletin N o. 61. Characteristics and Limitation of the Series Transformer, by A. R. Anderson 
and H. R. Woodrow. 1913. Twenty-five cents. 


Bulletin No. 62. The Electron Theory of Magnetism, by Elmer H. Williams. 1913. Thirty-five 
cents. 

Bulletin No. 63. Entropy-Temperature and Transmission Diagrams for Air, by C. R. Richards. 

1913. Twenty-five cents. 


*Bulletin No. 64■ Tests of Reinforced Concrete Buildings Under Load, by Arthur N. Talbot and 
Willis A. Slater. 1913. Fifty cents. 

*Bulletin No. 65. The Steam Consumption of Locomotive Engines from the Indicator Diagrams, 
by J. Paul Clayton. 1913. Forty cents. 

Bulletin No. 66. The Properties of Saturated and Superheated Ammonia Vapor, by G. A. Good- 
enough and William Earl Mosher. 1913. Fifty cents. 

Bulletin No. 67. Reinforced Concrete Wall Footings and Column Footings, by Arthur N. Talbot. 
1913. Fifty cents. 


*Bulletin No. 68. Strength of I-Beams in Flexure, by Herbert F. Moore. 1913. Twenty cents. 


Bulletin No. 69. Coal Washing in Illinois, by F. C. Lincoln. 1913. Fifty cents. 


Bulletin No. 70. The Mortar-Making Qualities of Illinois Sands, by C. C. Wiley. 1913. Twenty 
cents. 

Bulletin No. 71. Tests of Bond between Concrete and Steel, by Duff A. Abrams. 1914. One 
dollar. 

*Bulletin No. 72. Magnetic and Other Properties of Electrolytic Iron Melted in Vacuo, by Trygve 
D. Yensen. 1914. Forty cents. 

Bulletin No. 73. Acoustics of Auditoriums, by F. R. Watson. 1914. Twenty cents. 

*Bulletin No. 74 • The Tractive Resistance of a 28-Ton Electric Car, by Harold H. Dunn. 1914. 
Twenty-five cents. 

Bulletin No. 75. Thermal Properties of Steam, by G. A. Goodenough. 1914. Thirty-five cents. 

Bulletin No. 76. The Analysis of Coal with Phenol as a Solvent, by S. W. Parr and H. F. Hadley. 

1914. Twenty-five cents. 

*Bulletin No. 77. The Effect of Boron upon the Magnetic and Other Properties of Electrolytic 
Iron Melted in Vacuo, by Trygve D. Yensen. 1915. Ten cents. 

*Bulletin No. 78. A Study of Boiler Losses, by A. P. Kratz. 1915. Thirty-five cents. 

*Bulletin No. 79. The Coking of Coal at Low Temperatures, with Special Reference to the Prop¬ 
erties and Composition of the Products, by S. W. Parr and H. L. Olin. 1915. Twenty-five cents. 

*Bulletin No. 80. Wind Stresses in the Steel Frames of Office Buildings, by W. M. Wilson and 
G. A. Maney. 1915. Fifty cents. 

*Bulletin No. 81. Influence of Temperature on the Strength of Concrete, by A B. McDaniel. 

1915. Fifteen cents. 

Bulletin No. 82. Laboratory Tests of a Consolidation Locomotive, by E. C. Schmidt, J. M. Snod¬ 
grass and R. B. Keller. 1915. Sixty-five cents. 

*Bulletin No. 83. Magnetic and Other Properties of Iron-Silicon Alloys. Melted in Vacuo, by 
Trygve D. Yensen. 1915. Thirty-five cents. 

Bulletin No. 84. Tests of Reinforced Concrete Flat Slab Structure, by A. N. Talbot and W. A. 
Slater. 1916. Sixty-five cents. 

*Bulletin No. 85. Strength and Stiffness of Steel Under Biaxial Loading, by A. J. Becker. 1916. 
Thirty-five cents. 

*Bulletin No. 86. The Strength of I-Beams and Girders, by Herbert F. Moore and W. M. Wilson. 

1916. Thirty cents. 

*Bulletin No. 87. Correction of Echoes in the Auditorium, University of Illinois, by F. R. Watson 
and J. M. White. 1916. Fifteen cents. 

Bulletin No. 88. Dry Preparation of Bituminous Coal at Illinois Mines, by E. A. Holbrook. 1916. 
Seventy cents. 


* A limited number of copies of bulletins starred is available for free distribution. 



46 


PUBLICATIONS OF THE ENGINEERING EXPERIMENT STATION 


*Bulletin No. 89. Specific Gravity Studies of Illinois Coal, by Merle L. Nebel. 1916. Thirty 
cents. 

*Bulletin No. 90. Some Graphical Solutions of Electric Railway Problems by A. M. Buck. 1916. 
Twenty cents. 

*Bulletin No. 91. Subsidence Resulting from Mining, by L. E. Young and H. H. Stock. 1916. 
One dollar. 

*Bulletin No. 92. The Tractive Resistance on Curves of a 28-Ton Electric Car, by E. C. Schmidt 
and H. H. Dunn. 1916. Twenty-five cents. 

*Bulletin No. 98. A Preliminary Study of the Alloys of Chromium, Copper, and Nickel, by D. F. 
McFarland and O. E. Harder. 1916. Thirty-five cents. 

*Bulletin No. 94. The Embrittling Action of Sodium Hydroxide on Soft Steel, by S. W. Parr. 
1917. Thirty cents. 

*Bulletin No. 95. Magnetic and Other Properties of Iron-Aluminum Alloys Melted in Vacuo, by 
Trygve D. Yensen and Walter A. Gatward. 1917. Twenty-five cents. 

*Bulletin No. 96. The Effect of Mouthpieces on the Flow of Water Through a Submerged Short 
Pipe, by Fred B. Seely. 1917. Twenty-five cents. 

*Bulletin No. 97. Effects of Storage Upon the Properties of Coal, by S. W. Parr. 1917. Twenty 
cents. 

*Bulletin No. 98. Tests of Oxyacetylene Welded Joints in Steel Plates, by Herbert F. Moore. 
1917. Ten cents. 

Circular No. 4 • The Economical Purchase and Use of Coal for Heating Homes, with Special 
Reference to Conditions in Illinois, 1917. Ten cents. 

*Bulletin No. 99. The Collapse of Short Thin Tubes, by A. P. Carman. 1917. Twenty cents. 

*Circular No. 5. The Utilization of Pyrite Occurring in Illinois Bituminous Coal, by E. A. 
Holbrook. 1917. Twenty cents. 


* A limited number of copies of bulletins starred is available for free distribution. 














































































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THE UNIVERSITY OF ILLINOIS 
THE STATE UNIVERSITY 
Urbana 

Edmund J. James, Ph. D., LL. D., President 


THE UNIVERSITY INCLUDES THE FOLLOWING DEPARTMENTS: 
The Graduate School 

The College of Liberal Arts and Sciences (Ancient and Modern Languages and 
Literatures; History, Economics, Political Science, Sociology; Philosophy, 
Psychology, Education; Mathematics; Astronomy; Geology; Physics; Chemistry; 
Botany, Zoology, Entomology; Physiology; Art and Design) 

The College of Commerce and Business Administration (General Business, Bank¬ 
ing, Insurance, Accountancy, Railway Administration, Foreign Commerce; 
Courses for Commercial Teachers and Commercial and Civic Secretaries) 

The College of Engineering (Architecture; Architectural, Ceramic, Civil, Electrical 
Mechanical, Mining, Municipal and Sanitary, and Railway Engineering) 

The College of Agriculture (Agronomy; Animal Husbandry; Dairy Husbandry: 
Horticulture and Landscape Gardening; Agricultural Extension; Teachers 
Course; Household Science) 

The College of Law (three years’ course) 

The School of Education 

The Course in Journalism 

The Courses in Chemistry and Chemical Engineering 
The School of Railway Engineering and Administration 
The School of Music (four years’ course) 

The School of Library Science (two years’ course) 

The College of Medicine (in Chicago) 

The College of Dentistry (in Chicago) 

The School of Pharmacy (in Chicago; Ph. G. and Ph. C. courses) 

The Summer Session (eight weeks) 

Experiment Stations and Scientific Bureaus: U. S. Agricultural Experiment 
Station; Engineering Experiment Station; State Laboratory of Natural His¬ 
tory; State Entomologist’s Office; Biological Experiment Station on Illinois 
River; State Water Survey; State Geological Survey; U. S. Bureau of Mines 
Experiment Station. 

The library collections contain (July 1, 1917) 400,720 volumes and 102,029 pam¬ 
phlets. 

For catalogs and information address 

THE REGISTRAR 

Urbana, Illinois 





LIBRARY OF CONGRESS 


0 002 962 178 0 














































































































































